A wireless communication apparatus is equipped with means for suppressing consumption of operating power at standby, namely a power-saving control function, in order to reduce power consumption. This power-saving control function will be described in brief. First, a receive frame is divided into two periods, namely a first period and a second period. In the first period, a notification signal indicating whether there is distribution of data to each of a number of terminals is transmitted. In the second period, reception power is maintained as usual if there is data the destination of which is the local apparatus, and reception power is lowered if receive data is accepted and there is no data the destination of which is the local apparatus.
By thus dividing processing for receiving a signal notifying of data distribution and actual data, needless reception power can be reduced.
In accordance with the IEEE 802.11 standard, there is a power management function for suppressing amount of terminal battery consumption as the above-mentioned power-saving control function. With regard to utilization of a terminal power-saving mode, application to an infrastructure mode possessing a base station is clearly determined by specifications.
However, in an adhoc network in which terminals communicate with each other directly by sharing a network identifier without the intermediary of a specific base station, either a function for recognizing the power-saving state of a terminal participating in the network does not exist or recognition cannot be performed accurately. As a result, if the power-saving mode is utilized, there are problems such as instances where data cannot be received normally.
Consequently, if a terminal A activates the power-saving mode at the time of standby and data addressed to terminal A is sent in a state in which reception power has been lowered, then the data cannot be received. In particular, if an IP-address confirmation packet (ARP Request) is sent and a response to this packet cannot be made, there is a possibility that another terminal will acquire the same IP address.
By way of example, if another terminal B happens to acquire the same IP address, then data directed to terminal B will be sent to terminal A and terminal A will process this data. Terminal A will thus receive unnecessary data and execute needless processing. Further, terminal B will respond to data directed to terminal A and normal communication may be lost.